[98.01] LGS-AO: the making of a star for astronomy.

D. Le Mignant (W. M. Keck Observatory)

For astronomers, it all started in 1985 when Foy and
Labeyrie (1985, A&A, 152, L29)published the concept of
creating a laser guide star (LGS) in the mesospheric layer
of the atmosphere to extend the use of adaptive optics (AO)
to a much larger fraction of the astronomical sky. Shortly
thereafter, the first sodium wavelength laser beam was
propagated from Mauna Kea to validate the LGS concept
(Thompson & Gardner 1987, Nature, 328, 229). In 1991, the
results from the research undertaken by the U.S. Dept. of
Defense were published in the open literature (Fugate et al.
1991, Nature, 353, 144). Experiments were subsequently
performed at a number of Observatories (Apache Point, MMT,
Calar Alto & Lick) resulting in one operational LGS-AO
facility on the Lick 3-m telescope (Max et al. 1997,
Science, 277, 1649).

Today, Keck II LGS-AO, the first operational LGS-AO facility
on an 8-10-m class telescope, is paving a new road for
astronomical science by providing very high angular
resolution (FWHMs of 50-60 mas with Strehls of 20-35% at K)
over half of the sky. AO-corrected imagers and spectrographs
at Keck and elsewhere will soon be used by a wider community
of astronomers to complement and frequently surpass the
observations obtained from space.

We will present a review and a discussion of this powerful
new instrumentation: the exciting scientific showcases and
the challenges for combining complicated dynamic systems
into productive, reliable and user-friendly instrumentation.
We will provide an update on the forthcoming LGSAO
intruments at other major observatories. We will report on
the image quality performance, as well as on-sky observing
efficiency, for the Keck II system (Wizinowich et al. 2005,
PASP, submitted).

As many astronomers plan for "AO all-the-time" on large and
extremely large telescopes, this talk will provide some
information and lessons learned for how to best prepare for
the bright LGS-AO future.

The author(s) of this abstract have provided an email address
for comments about the abstract:
davidl@keck.hawaii.edu